1. Field of the Invention
The present invention relates to processing of digitized speech and more particularly to compression of voice data to reduce bandwidth required to transmit the speech over digital transmission media while preserving perceptual speech quality.
2. Background of the Art
With the current growth of digital transmission and the convergence of voice and data networks world-wide, digitized speech signals place increasing bandwidth burdens on digital networks. Existing fixed and variable rate speech compression techniques suffer from poor speech quality in the reconstructed speech and lack the flexibility to adapt dynamically to changing network bandwidth constraints.
Contemporary digital transmission environments beneficially accommodating variable data rates include multi-channel long-haul telecom, and voice over Internet Protocol (IP) applications.
The current trend in IP networks toward a quality-of-service (QoS) based rate structure is supported to only limited extents by existing voice compression systems, which generally offer a limited range of data rates and output speech quality.